1. Field
Embodiments relate to an apparatus, method, and medium for dividing regions by using feature points and a mobile robot using the same and, more particularly, to an apparatus, method, and medium for dividing regions by extracting both end points of a gateway from feature points and a mobile robot using the same.
2. Description of the Related Art
Generally, robots have been developed for industrial purposes to be used in repetitive operations as a part of factory automation. In recent years, in addition to an industrial robot, various kinds of robots have been put to practical use, particularly, a human-friendly robot which moves by itself in a household or an office to work in place of humans. For example, the robots include a robot cleaner, a security robot, a guide robot, a service robot, etc.
In a mobile robot such as a robot cleaner, it is necessary to distinguish regions to clean. For example, in a robot cleaner, if a user gives a command to clean regions such as a room, a living room and a kitchen, the robot cleaner should be capable of distinguishing and recognizing a room, a living room, a kitchen or the like to clean. In order to carry out these operations, the robot should be capable of exactly displaying the entire space as a grid map, and the grid map stored in the robot should be divided into regions (topological map) such as a room and a living room in order to allow a user to give a command to clean the regions.
As a method of dividing regions, there is known a method in which a gate is recognized as a reference for dividing regions. A method of dividing rooms by recognizing entrance doors is disclosed (see, for example, Japanese Patent Laid-Open No. 2005-211359), in which a robot cleaner recognizes signposts installed in the vicinity of entrances of rooms so as to detect doors by using sensors and cameras while moving, thus performing cleaning. Problems are found in this method. A signpost should be installed for each entrance door, which is cumbersome. Accordingly, if entrance doors are many, the cost is high. Further, if a cleaning space is switched, signposts should be newly installed.
FIG. 1 is a view sequentially showing a method of drawing a topological map by detecting a narrow path with a Voronoi diagram. First, when the shortest distance between obstacles is obtained in all grids of a free space, a voronoi diagram is drawn by connecting center points of the shortest distances (FIG. 1B). Each point in the voronoi diagram has a value of the shortest distance from obstacles, in the case in which the shortest distance has a local-minimum, a point of the voronoi diagram, that is, a point of the voronoi diagram having a local-minimum, when an X-axis is defined along the voronoi diagram and the distance to an obstacle of each point is defined as a Y-axis, is determined as a critical point (FIG. 1C). Next, a critical line is drawn by connecting points shortest distant from each critical point (FIG. 1D). This critical line is a narrow path which is extracted by the voronoi diagram. Each region divided by the critical lines becomes a topological region (FIG. 1E).
In the related art, a lot of calculations are needed because the shortest distances from all grids of a free space to the obstacles should be obtained. In addition, since an actual map has too many inconsistencies, unnecessary critical points are generated, such that an unexpected delicate region is generated in a topological map.
Exemplary embodiments described hereinafter overcome the drawbacks inherent in the related and provide an apparatus, method, and medium for dividing regions by detecting a gateway from feature points by reducing the amount of calculations.